The present invention is directed toward a method and apparatus for high-speed processing of fruit or the like and more particularly to such a method and apparatus wherein individual characteristics of individual units are sensed so that the units are sorted according to their individual characteristics.
A variety of techniques and apparatus have been disclosed in the prior art for automatically grading and sorting fresh fruit and the like according to size, surface blemishes, surface color and even internal characteristics of the fruit. In the latter case, X-ray detectors have been employed, for example, for automatically evaluating articles, particularly citrus fruit, on the basis of relative uniformity of transparency to X-rays for separating the fruit or other article into different grades according to such evaluation. Although the present invention is particularly concerned with such a method and apparatus adapted for the grading and sorting of fresh fruit and the like, such methods and apparatus may be adapted to sorting a variety of articles. Accordingly, the scope of the present invention is not strictly limited to the grading and sorting of fruit.
As the state of the art in the grading and sorting of fruit and the like has developed beyond manual sorting techniques, it has become particularly important to develop reliable methods and apparatus which are capable of accurately grading and sorting fruit at relatively high speeds. Once again, it is important that these operating characteristics be achieved regardless of whether the fruit or other article is being graded and sorted depending upon size, surface color, surface blemishes or even internal characteristics of the fruit or other article.
In connection with one particular aspect of the present invention, there has been found to remain a need for an improved method and apparatus for automatically grading and sorting articles such as fruit according to size where the fruit is initially available in random sizes. Manual sorting of fruit according to size was initially replaced by mechanical sizers. However, such mechanical sizers have been found to be somewhat inaccurate primarily because of irregular shapes exhibited by various units of fruit. Accordingly, improved techniques for sizing fruit and the like have been developed in the prior art. One such prior art development by the assignee of the present invention involved optical sensing of size characteristics of the fruit in a manner permitting much more accurate determination of the volume of the fruit regardless of its particular shape. This optical technique, although not a feature of the present invention by itself, is hereinafter referred to in order to permit a more complete understanding of the invention.
At the same time, either in connection with optical sizing of fruit as referred to above or in sorting the fruit and the like according to other characteristics, there has also been found to remain a need for improved machinery and methods of operation in order to achieve high speeds of operation necessary for efficiency while still maintaining accuracy.
In such high speed operations, it is initially important to assure that one and only one individual unit of fruit or the like is loaded into each receiving point on a conveyor for passage through the detector station. In achieving this object, it has been found that, in some methods and apparatus for processing fruit or the like, particularly where random sizes are involved, more than one unit may become lodged in a single receiving point on the processing conveyor. This is, of course, unacceptable since the detector is generally not capable of determining whether it is scanning one or more articles.
In addition to the problem of singulation as summarized above, it has also been found to be difficult to properly locate each individual unit of fruit or the like in a conveyor during passage through a suitable detector or the like. A similar problem has been found to exist in assuring proper exposure of each article to the detecting station, particularly when the detector employs optical means which must necessarily scan a substantial surface portion of the article.
Finally, it has also been found desirable to develop improved techniques for discharging individual units of fruit or the like into respective discharge passages according to their individual characteristics while assuring relatively gentle handling of the articles during the entire processing in order to prevent further damage.
In any event, there has been found to remain a need for an improved method and apparatus for achieving the high speed sorting or grading of articles such as fruit, particularly where the fruit or other article is initially supplied in random sizes.